Hello Sasikiran

As you have one backlog in diploma, you are not eligible to join any college because of that backlog . For joining a college, you first have to clear that backlog and then only you will be eligible to join B.Tech in any college as most universities require a pass certificate for diploma , meaning that you need to pass all the subject before the admission.

So study hard and clear that backlog. You are just one step away from your dream college.

Thank you!!!

Without completing your diploma, you can't do B.E or B.Tech.  It is always better first to complete your backlog immediately. Then you can give a try by appearing in the entrance test conducted by many universities for getting admitted to B.Tech 2nd year. If you are unable to do so then the option you have is to write open University direct B.A. entrance test and study BA.
But it is a clever idea to complete diploma at the earliest.