user: Question: How many days were the station of Soyuz 35 in flight down were in orbit?
Columns: ['Expedition', 'Crew', 'Launch date', 'Flight up', 'Landing date', 'Flight down', 'Duration (days)']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Salyut 6 - EO-1', 'Yuri Romanenko , Georgi Grechko', '10 December 1977 01:18:40', 'Soyuz 26', '16 March 1978 11:18:47', 'Soyuz 27', '96.42']
SQL:

assistant: SELECT "Duration (days)" FROM "Table" WHERE "Flight down" = 'Soyuz 35';