user: Question: Which design has a serial format of AB-12-34?
Columns: ['Issued', 'Type', 'Design', 'Serial format', 'Serials issued']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['1973- 1974', 'Passenger', 'yellow on blue', 'AB-12-34', 'AA-00-00 to ZZ-99-99']
SQL:

assistant: SELECT "Design" FROM "Table" WHERE "Serial format" = 'AB-12-34';