LLB after graduation

Since you did your graduation, you should opt for 3 Years course. Yes, most of the State had prescribed entrance test for taking admission in LL.B. course. Like Maharashtra had MH-CET. If you want to do LL.B. from National Law School then CLAT Exam is there. You will find details in respect of this course in Tanuj Kalia's Book Law as Profession.

I don’t know why you want to pursue LLB.  Your intentions are not known to me.
Let me clarify few things before you plunge in.

LLB – 3 years course. – qualification degree/post graduate degree.
BA LLB – 5 years course. – qualification PUC sufficient.

Entrance exam need to be cleared – CLAT.  Then you need to choose any of the above.

Both courses need to be done full time.  No correspondence course available in India.

What will happen if you complete LLB?
You need to clear bar exam if you want to practice as advocate.
If you don’t want to practice, you can go to Bombay and apply for notary exam, price is 50000/-
You can go to corporate field (MNCs) there you apply for legal advisor job, but you will be given full time clerical job.  You will rarely get cases to fight in court on behalf of company.

Lawyer profession was noble profession once upon a time.  These days only those people who don’t get any seat anywhere they come to legal course which is LLB.  Such students do not excel anywhere.  These days passing LLB is tough, they seem to have set high standards but the judiciary standards are the same as ever.
There is no respect for Lawyers anymore, mainly because of lawyers cheating their clients.  You can watch Jolly LLB 1 and 2 for other details as to how much respect Lawyers have in real life.

Instead of pursuing LLB, you pursue MBA, atleast you can lead dignified life.  With LLB you will have to spend initial years hunting for clients, which is like Indian monsoon, if clients come you will have money, that too if they give, not all clients give money promptly.  Other option is joining law firms.  They loot collectively.  There is scope to loot people there.

See what suits you and decide.