Dear aspirant

For any degree/graduation,you must pass your class 12th exam.

That is basic eligibility and then only you will eligible for promotion in the Higher classes .

Without passing you class 12th you can persue any graduate/degree courses.

Also now days you need good marks in class 12th to get good degree college also.

So you must appear for supplementary exam if you have failed in class 12th or you must reappear next year and pass your class 12th to persue degree.

Hope this information helps you

All the best!!