CREATE TABLE table_34218 ("Callsign" CLOB, "Area served" CLOB, "Frequency" CLOB, "Band" CLOB, "On-air ID" CLOB, "Purpose" CLOB)

what is the callsign whtat uses 7bu?
SELECT "Callsign" FROM table_34218 WHERE "On-air ID" = '7bu'
SELECT "Callsign" FROM "table_34218" WHERE "On-air ID" = '7bu'