user: Question: What is the Call Sign of the Frequency by Owner CKUA Radio Foundation?
Columns: ['Frequency', 'Call sign', 'Branding', 'Format', 'Owner']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['00 91.1', 'CKOS-FM', 'KAOS 91.1', 'Christian', 'King’s Kids Promotions Outreach Ministries']
SQL:

assistant: SELECT "Call sign" FROM "Table" WHERE "Owner" = 'CKUA Radio Foundation';