user: Question: For which league is the open cup the Quarter Finals
Columns: ['Year', 'Division', 'League', 'Regular Season', 'Playoffs', 'Open Cup']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1991.0, 'N/A', 'SISL', '4th, Southeast', 'Did not qualify', 'Did not enter']
SQL:

assistant: SELECT "League" FROM "Table" WHERE "Open Cup" = 'Quarter Finals';