user: Question: What's the call sign that has 20kW of power?
Columns: ['Branding', 'Call-Sign', 'Frequency', 'Power (kw)', 'Location']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['702 DZAS', 'DZAS', '702kHz', '50kW', 'Metro Manila']
SQL:

assistant: SELECT "Call-Sign" FROM "Table" WHERE "Power (kw)" = '20kW';