When filing the state taxes, the medical portion of auto insurance premiums is found where? Is that the PIP expense on the auto policy?

Assuming that you're asking this question in the context of the Michigan property tax credit, Personal Injury Protection (PIP) would qualify only to the extent that it covers medical expenses.  Some PIP also covers lost wages, which would not count; you may need to check with your insurer to see what your PIP might cover.

The relevant portion of your auto insurance premium would be displayed on your auto insurance coverage document as Automobile Medical Payments Coverage, or something similar.  It typically includes payments for medical treatment needed as a result of an auto accident.

See Health Insurance Premiums and Total Household Resources and See Line 31 in the Form MI-1040CR Instructions for more information.