user: Question: When Salyut 7 – VE-4 – EVA 1 is the spacecraft, what is the duration?
Columns: ['Spacecraft', 'Spacewalker', 'Start – UTC', 'End – UTC', 'Duration', 'Comments']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Salyut 7 – PE-1 – EVA 1', 'Lebedev, Berezevoi', '30 July 1982 02:39', '30 July 1982 05:12', '2 h, 33 min', 'Retrieve experiments']
SQL:

assistant: SELECT "Duration" FROM "Table" WHERE "Spacecraft" = 'Salyut 7 – VE-4 – EVA 1';