user: Question: List all GT4 Cup winners played on the Spa-Francorchamps Report.
Columns: ['Event', 'Circuit', 'GT3 Pro Cup Winner', 'GT3 Pro / Am Cup Winner', 'GT3 Citation Cup Winner', 'GT4 Cup Winner']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Monza', 'No. 9 AutOrlando Sport', 'No. 24 Blancpain Reiter', 'No. 31 Ruffier Racing', 'No. 70 Lotus Italia Scuderia Giudici']
SQL:

assistant: SELECT "GT4 Cup Winner" FROM "Table" WHERE "Circuit" = 'Spa-Francorchamps Report';