you must passed BA with english from UGC approved college.
there is no percentage for MA admission. the eligibility criteria is a graduation degree with english and 55% marks as aggregate in B.A. In some colleges the selection is purely merit based while in other there is an entrance test of which eligibility is 55%. You can apply in any university for the post of Asst. Professor
and as you also have the teaching experience you will get the
priority over the other candidates applying for the same post.