Mtech, MS, PhD, project assistant or associate, all of these programs can get you stipend.

Mtech, you get through GATE,INR 12400 stipend, direct admission.

MS, you get through GATE but you have to face an interview, INR 12400 stipend.

Same for PhD but stipend is around INR25000.

Project assistant and associate, you can get by contact of a professor in IIT or by a small interview after the prof goes through your CV, you have to apply for it. Stipend can be around INR 20000 if you are an Mtech or INR 15000 if you are a Btech . The stipend varies for this program since you can be deployed in a project which is company sponsored and you may get extra money if your prof is willing.

The TA duties that are assigned to us are nothing out of ordinary. You may be assigned to help your department with admission process or you may have to help out in departmental labs or if you are say assigned to a particular subject then you will probably help the teacher with making/grading tutorials and conducting exams etc.

Thankyou, I hope it helps, feel free to approach for further queries.