user: Question: Name the slope length for 1966 groundstation
Columns: ['Name or route', 'type', 'elevation groundstation', 'elevation mountainstation', 'slope length', 'capacity in persons/hour', 'construction year(s)']
Types: ['text', 'text', 'real', 'real', 'real', 'real', 'text']
Sample row: ['Betten Betten Village', 'aerial tramway', 832.0, 1199.0, 872.0, 350.0, '1950 1965']
SQL:

assistant: SELECT "slope length" FROM "Table" WHERE "elevation groundstation" = 1966.0;