Yes you can take mil subjects like punjabi, sanskrit in du even if you have not studied it in class 12 provided you have studied it till class 10th and have atleast 40% marks in it. You won't get admission without it. This is valid for opting for these subjects in both hons courses and in ba programme.

All the very best. 

You can check you chances of getting into du with the college predictor at https://www.careers360.com/college-predictor