Hi,
If you are applying for BA.LLB in sastra law school tanjavur than you have less percentage in 12th class and there is no merit based admission. You have to give CLAT entrance exam to get admission. The minimum weightage is 75% marks in +2 and minimum 25% marks in clat exam.
I suggest you to give the Clat exam as you may get admission in NLUs in India if you get good marks in Clat . But the exam application form has been ended so you have to try next year for the CLAT exam.