user: Question: What is the duration of the flight with end time of 21:06?
Columns: ['Start Date/Time', 'Duration', 'End Time', 'Spacecraft', 'Crew']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['10 March 16:22', '4 hours 49 minutes', '21:11', 'Expedition 18 ISS Pirs', 'Yuri Lonchakov Michael Fincke']
SQL:

assistant: SELECT "Duration" FROM "Table" WHERE "End Time" = '21:06';