No, you are not eligible for LSAT exam if you belongs to general. The minimum percentage is 45. But If you belongs to reserved category then there is some relaxation in marks.
For more details about LSAT India:-
I hope this helpful for you.
Sorry, but unfortunately with 42 percentage in your 12th examinations you are not eligible to give LSAT examination 2020. You can try some private colleges or get a drop year and give your 12th boards again. The minimum requiremnt is 45 percentage
All the best.