user: Question: Name the lowest Year Joined which has a Mascot of Pioneers?
Columns: ['School', 'Location', 'Mascot', 'Enrollment', 'IHSAA Class', 'County', 'Year Joined', 'Previous Conference']
Types: ['text', 'text', 'text', 'real', 'text', 'text', 'real', 'text']
Sample row: ['Decatur Central', 'Indianapolis, IN', 'Hawks', 1856.0, 'AAAAA', '49 Marion', 2006.0, 'Conference Indiana']
SQL:

assistant: SELECT MIN("Year Joined") FROM "Table" WHERE "Mascot" = 'Pioneers';