user: Question: Which Frequency MHz has an ERP W larger than 4, and a Call sign of W218AP?
Columns: ['Call sign', 'Frequency MHz', 'City of license', 'ERP W', 'FCC info']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['W207AF', '89.3 FM', 'Meadville, PA', 4.0, 'FCC']
SQL:

assistant: SELECT "Frequency MHz" FROM "Table" WHERE "ERP W" > 4.0 AND "Call sign" = 'W218AP';