Hello Saba Ul-lah, 

In most state boards for higher secondary exam, you do not qualify the exam if you do not pass in all subjects. Therefore even if you failed in one subject, you will have to re-apply/retake the test again for that particular subject to qualify your 10+2 examination. If you do not qualify your 10+2 exam you cannot apply to almost any college, therefore, you also cannot apply to Jamia Milia Islamia. 

Qualification rules may vary according to states/boards. Mention your particular board next time for a more specific answer.

Hope this helps.