I am from OBC category and I have got 45 percentile in CAT. Which colleges can I apply?

Prajwal, with this percentile it is doubtful that you can get a good college. There are different ways of admission in MBA. Some institutes prefer XAT/ MAT/ CMAT/ GMAT scores too for admission to MBA course. Another way of admission is internal tests or admission criteria of individual Management

It will be very difficult for you to get a good college. I would suggest you to prepare better for the other upcoming management exams such as CMAT, MAT and ATMA.