YES, you will have to submit original failed marksheet if you apply through demand examon the basis of which you are availing credit facility. In case of not doing so, your result will not be declared, it will be withheld until you submit your original marksheet. Hope you have received answer of your queries.

NIOS TOC program is open to students who haven't failed in all subjects during their 10th and 12th-grade exams from any recognized board. If you have an original mark sheet showing that you've passed some subjects, you're eligible for TOC in NIOS.