GC NET/SET/SLET is the minimum eligibility for appointment of Assistant Lecturership in any Indian University or college (including Delhi University) recognised by the Government of India.
If you have already cleared UGC NET examination (no other paper is conducted for the recruitment of Assistant Professors in Delhi University), you can apply for lecturership right-away.
After clearing UGC NET JRF a candidate becomes eligible for the designation of Assistant Professor at any university across India. But this is also a fact that the vacancies are less in government universities as compared to private universities.