CLAT Entrance exam is only for the admission of (5 years law & LLM) programme, It is not for LLB (3 years law ) programmes. There are many universities for LLB programme some of the universities take the admission through an entrance exam & some of the universities takes the admission on the basis of merit list. After completing B.Sc programme here are some of the top univresities for LLb programme you can apply:

University of Delhi, DULLB- Its own entrance DUllb entrance exam

Faculty of Law Banaras Hindu University- BHU llb entrance Exam

Government Law colleges Mumbai- MH CET law

ILS Law college Pune- MH CET law

Good Luck!