HI,

Let me clear you take TSICET IS for admission in post gradution courses MBA and MCA ,Not for degree course 

Yes you can do first your degree course from a recognised university and then appear for TSICET for futher studies

more over 

for seeking admission for MBA should have passed recognized Bachelors Degree Examination of minimum three years duration except Oriental Languages.

For  admission in MCA should have passed recognized Bachelors Degree examination of minimum three years duration (except Oriental Languages) with Mathematics at 10+2 level.

The qualifying Degree obtained by Distance Mode Program should have recognition by joint committee of UGC, AICTE and DEC/DEB.

GOOD LUCK