user: Question: Which IHSAA Football Class has a County of 77 Sullivan, and a School of Union Dugger?
Columns: ['School', 'Location', 'Mascot', 'Enrollment', 'IHSAA Football Class', 'County']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Eastern Greene', 'Bloomfield', 'Thunderbirds', 406.0, 'A', '28 Greene']
SQL:

assistant: SELECT "IHSAA Football Class" FROM "Table" WHERE "County" = '77 Sullivan' AND "School" = 'Union Dugger';