Hello Swati, 

The Banaras Hindu University provides M. Sc. in Forensic Science and overall there are 30 seats for intake. The average cutoff rank moves around 145-155 most of the time and as you have mentioned that your OBC rank is 113,so it will be quiet difficult for me to tell about your common rank. You will get a better idea based on the stats provided to you.

Hope it helped you.  :)