user: Question: Who was the radio commentator when the final television commentator was John Dunn? 
Columns: ['Year(s)', 'Final television commentator', 'Radio commentator', 'Spokesperson', 'Semi-final television commentator', 'Semi-final second television commentator']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1956.0, 'Wilfrid Thomas', 'Unknown', 'UK did not participate', 'No semi-finals', 'No semi-finals']
SQL:

assistant: SELECT "Radio commentator" FROM "Table" WHERE "Final television commentator" = 'John Dunn';