what is the name of the field in database for "Responsible Tester" ?

I want to put some value in "Responsible Tester" field for each Test in a Testset.

but to access this, I need to know the FIELDNAME of this field in the database, so that i can use that name in the below code.

TSTest.Field("<FIELDNAME>") = "Any string"

How do we generally access the TSTest fields. For eg:; we access the fields of a Step using "ST_.." and fields of the RUN as "RN_..."..in the same way how do we access the fields of a particular test..I tried "TS_.." and "TST_''"...nothing works..