Hello,

Law courses are of two types, that is integrated law programs  for a duration of five years, this comes in many forms such as BA-LLB, BBA-LLB, BCom-LLB, BCA-LLB etc, as the name suggest it's integration of law with the corresponding subject such as commerce in BCom-LLB, management in BBA-LLB etc, the eligibility criteria for this is passed 10+2 from a recognized board with 45% aggregate, some of the top entrance exams are AILET, CLAT, LSAT to name a few, in some colleges admission is also done based on the merit of the qualifying examination.

The second one is LLB which is for a duration of three years, and the eligibility criteria is passed graduation in any discipline from a recognized board with 45-50% aggregate, you can consider Delhi University, Allahabad University, Banaras Hindu University etc they conduct their own entrance test, similarly in some colleges admission is also based on the merit of the qualifying examination.

There are also state level exams for both five year and three year admission such as AP LAWCET in Andhra Pradesh, TS LAWCET in Telangana, KLEE in Kerala, MAHCET LAW in Maharashtra.

Law as a degree whether it's of five or three years duration doesn't have any such specific requirement of belonging to any specific stream at 10+2 or graduation level respectively.