user: Question: Which freq currently has 0 684?
Columns: ['Callsign', 'Area served', 'Frequency', 'Band', 'Freq currently', 'Purpose']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['5AL', 'Alice Springs', '1530', 'AM', '8AL (783 kHz)', 'National']
SQL:

assistant: SELECT "Freq currently" FROM "Table" WHERE "Frequency" = '0 684';