Hey Kalyani,
As your question is not so clear but still I am answering it upto my experience,
You can do Diploma (in any course) easily after 10th with 77% marks.
After 12th if you pursue for the same course, then because of your diploma you can get admission in second year of your Bachelor's degree(of same course), this is called lateral entry. You have to especially fill for lateral entry forms in that particular course after 12th.
If I have misunderstood your question, kindly ask any query in comments.
Hope it helps!