user: Question: Which Call Sign that has a Tail Code of OY belong to Weapon Systems Officer Capt Charles B. DeBellevue?
Columns: ['Date', 'Pilot', 'Weapon Systems Officer', 'Aircraft', 'Tail Code', 'Call Sign', 'Kill']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['May 10', 'Capt Richard S. Ritchie', 'Capt Charles B. DeBellevue', 'F-4D 66-7463', 'OY', 'Oyster 03', 'MiG-21']
SQL:

assistant: SELECT "Call Sign" FROM "Table" WHERE "Tail Code" = 'OY' AND "Weapon Systems Officer" = 'Capt Charles B. DeBellevue';