If you wish to sit for UP PGT then you need to have a Masters Degree. Now if you want to go for the Masters in Sociology then in general for most of the universities they will ask for a degree in the subject of Sociology or Arts. So its very less that you will be eligible for the course of Masters in the field of Arts and sociology. I would recommend you to check the eligibility criteria in the university you want to take admission in and check the eligibility criteria. There can be exceptions.

I hope this answer helps. All the very best for your future endeavors!