user: Question: Who is the winner when BigTen (2-1) is the challenge leader?
Columns: ['Date', 'Time', 'ACC Team', 'Big Ten Team', 'Location', 'Television', 'Attendance', 'Winner', 'Challenge Leader']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Mon., Dec. 1', '7:00PM', 'Virginia Tech', '#22 Wisconsin', 'Cassell Coliseum • Blacksburg, VA', 'ESPN2', 9847.0, 'Wisconsin (74-72)', 'BigTen (1-0)']
SQL:

assistant: SELECT "Winner" FROM "Table" WHERE "Challenge Leader" = 'BigTen (2-1)';