user: Question: What is K236AM's lowest frequency in MHz?
Columns: ['Call sign', 'Frequency MHz', 'City of license', 'ERP W', 'Class', 'FCC info']
Types: ['text', 'real', 'text', 'real', 'text', 'text']
Sample row: ['K297AL', 107.3, 'Dighton, Kansas', 170.0, 'D', 'FCC']
SQL:

assistant: SELECT MIN("Frequency MHz") FROM "Table" WHERE "Call sign" = 'K236AM';