Petitions are due this week for congressional candidates who want to be on the ballot in the June primary. More than 12,000 signatures from registered party members are required.  The process could narrow the field in some of the more crowded contests, like the 21st congressional district, where several Democrats are lining up to take on Republican Congresswoman Elise Stefanik. Business owner Tedra Cobb announced her candidacy last summer and is confident she will make the cut for June.