Hello Shweta,
To apply for a Ph.D. you need to have a minimum of a masters degree with at least 55% of marks, also you need to have a good research proposal as to why you intend to do Ph.D. and what will be your topic or area of research. 
Having said that I guess it will be difficult for you to get admission having only 1 year of MBA, so complete your MBA and then only apply for Ph.D., even after that you need to sit in their entrance exam and interview and only after that if you are selected you secure a seat.
You can also give NET exam to avoid the entrance test for examination. 

Hope this helps,
Good Luck!