NOC confusion (NOC 4011 or 4021)

[abhi4001]

Please guys help me in choosing NOC for express entry profile. I am working as an Assistant professor in a University, but their are different schools within the university. I am teaching diploma students from the past 3 years which is under School of polytechnic. so which NOC should i choose 4011 or 4012, as my roles and reponsibilities are of 4012 and we give diploma to the students.