user: Question: Which Previous conference hAs A YeAr joined smAller thAn 1976, And An IHSAA ClAss of A?
Columns: ['School', 'Location', 'Mascot', 'Enrollment', 'IHSAA Class', '# / County', 'Year joined', 'Previous conference']
Types: ['text', 'text', 'text', 'real', 'text', 'text', 'real', 'text']
Sample row: ['Manchester', 'North Manchester', 'Squires', 434.0, 'AA', '85 Wabash', 1976.0, 'Northern Lakes']
SQL:

assistant: SELECT "Previous conference" FROM "Table" WHERE "Year joined" < 1976.0 AND "IHSAA Class" = 'A';