Nowadays, B. Ed is essential requirement for becoming teacher in private as well as govt school. As mentioned above, you have been working in school as a teacher since long time so, school authority not demanding B. ED degree. But, in govt school without B. Ed you would not be eligible for teaching and higher post. As you having long experience of different field so, school management should consider about your candidature for the post of principal. But main fact is, everywhere competition is there and if some candidate having more qualification and experience compare to you then how can you claim for principal post. Moreover, they consider many other factor also for the principal post like age, experience etc.
As far as Ph.D degree is concerned, it is essential requirement for lecturer post. Ph. D degree is not relevant for school related job.