Hii!
Your question is quite unclear.
If you want to join the defence forces, firstly you need to take PCM stream in class 12th. Then, you can go for NDA entrance examination and make your way through the field.
If you are enquiring about the Colleges providing  the  B.A in Defence and strategic studies ourse, then some of the Colleges are-
* Guru Nanak College, Chennai
* Jodhpur National University, Jodhpur
* Chandigarh University
* Dr. Ambedkar Government Arts College, Chennai
* Meerut College, Meerut
Etc.,
Hope you understand.
Good luck!