Hey Deepak.

Yes, if a candidate has completed an Undergraduate degree in any field including BCA from a recognised University, then he/she is very much eligible  for admission in 3 year LLB course. To be eligible to take admission through DU LLB in Delhi University you need to score a minimum aggregate of atleast 50% marks in your BCA degree to be eligible if you belong to the general category and 40% if your belong to the SC/ST category and 45% if you belong to the OBC/PWD category.

Best of luck