How can we create a sql in an expression to route the approval workflow to incumbent of the position

We created a DFF on a location which maps a position for HR Director, Director of Finance, and General Manager to the location. We’d now like to create a sql in an expression which will route the approval workflow to the incumbent of the position located on the location. For example, a pay change will look at the location of the Team Member, then the Director of Finance position designated on the location and send the approval to the incumbent of the position.