user: Question: How many challenge leaders were there of the games won by Virginia (87-79)?
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., Nov. 29', '7:00PM', 'Virginia', '#13 Minnesota', 'Williams Arena • Minneapolis, MN', 'ESPN2', 12089.0, 'Virginia (87-79)', 'ACC (1-0)']
SQL:

assistant: SELECT COUNT("Challenge Leader") FROM "Table" WHERE "Winner" = 'Virginia (87-79)';