user: Question: Name the broadcast date of 6.9 million viewers
Columns: ['Episode', 'Broadcast date', 'Run time', 'Viewers (in millions)', 'Archive']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['" Episode 1 "', '27April1968', '23:47', '7.2', 'Only stills and/or fragments exist']
SQL:

assistant: SELECT "Broadcast date" FROM "Table" WHERE "Viewers (in millions)" = '6.9';