user: Question: What is the frequency of Walterboro, SC?
Columns: ['Call sign', 'Frequency MHz', 'City of license', 'ERP W', 'Class', 'FCC info']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['W203BQ', '88.5 FM', 'Walterboro, SC', 30.0, 'D', 'FCC']
SQL:

assistant: SELECT "Frequency MHz" FROM "Table" WHERE "City of license" = 'Walterboro, SC';