user: Question: What Surface had a Rally HQ of Salou?
Columns: ['Round', 'Dates', 'Rally Name', 'Rally HQ', 'Support Category', 'Surface']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '11–14 February', 'Rally Sweden', 'Karlstad', 'PWRC/SWRC', 'Ice and snow covered gravel']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Rally HQ" = 'Salou';