Eligibility for teaching B.Com theory as an Assistant Professor

Once you complete your Ph D in the HR area, you will be eligible for teaching undergraduate students and PG students. You will be eligible for teaching to B.Com students with your PG qualifications also. For obtaining a teaching post in a college or University, you have to get qualified in the NET examination conducted by CBSE on behalf of CSIR/UGC. This examination will be conducted once in a year and you have to apply for the examination. The candidates who qualified in this examination may get scholarships also for their PhD studies.
There are some private colleges where they appoint candidates who have not qualified in the above examination also but the salary and other benefits will be less and they will not get aided posts.
So you concentrate on the NET examination and get qualified in that examination. Then only you will have more chances to get the lecturer post with UGC scales.

With the qualifications which you have already achieved, you are not entitled to teach the students of B.Com even though you qualify the NET test conducted by CBSE.
In order to be lecturer in HR area, you need to acquire the Ph.D degree under the guidance of the eminent professor from a recognised university and finally you have to secure a job by qualifying the interview to be conducted by the commission.
Alternatively, clear the NET test conducted by CBSE and for this, you need to secure the prescribed marks ie 55 percent for the general candidates and for OBC and SC/ ST a suitable relaxation of 5 and 10 percent will be offered respectively.
You will be appointed as a lecturer once you qualify the test subject to fulfilling other criterias such as prescribed marks and your fitness of your health condition of the medical board.
This would make you eligible to take up the courses for HRA but as the course content of B.Com is entirely different, you would not be allowed to teach commerce subjects.

For teaching the B.Com. classes one has to have a PG degree in commerce or its sub stream along with NET qualification. In your case you do not have that so it will not be possible to pursue that career line for you. But there is not a problem as you can try for lecturer ship in your core subjects like humanities or HR but you will have to go for NET also. Another thing is as you have done PhD in HR, you can get lecturer ship in HR subjects even without going for NET.

Please note that there are many aspirants for lecturer ship in their main core subjects and the other persons having degrees in other subjects do not stand chance there. So, one has to focus in his core subjects only for making a successful career.

Yes. Certainly Ph.D qualified candidates are eligible to the post of Assistant Professor. You can be promoted to higher posts eventually after getting enough experience in teaching. The next level is Associate Professor and then Professor. You should also try to concentrate on research area and publish some papers in reputed journals to add more credit to your teaching career. All the best to start your teaching career.