Hey Vikas.

If you've done BTECH already and now you are interested in pursuing Law, you can directly do an LLb course only.

Btech LLb is a 5 year Integrated course which combines and undergrad degree Btech along with Law. So if you pursue this course now you will be doing Btech twice.

Hence, instead of this you can simply do a 3 year LLB course which will include only Law. And btech graduates are also eligible for that.

Various top colleges for LLB course will be-

Delhi University 

GLC Mumbai

ILS Pune

IIT Kharagpur

Symbiosis Law School, Pune

Panjab University, Chandigarh

Banaras Hindu University 

Bharatiya Vidyapeeth, Pune 

Jindal Global Law school

And many more.

Best of luck