Canadian County’s County Commissioner District 3 seat will be filled during the June 28 primary. No Democrat filed during the April filing period. The two candidates who filed are both Republi cans: Robert Merrick, age 38, of Yukon, and Tracey Rider, age 60, of El Reno. For the past 12 years, Jack Stewart has served as County Commissioner for District 3. However, the seat is open because Stewart…