user: Question: What is the number of leg for SS17
Columns: ['Leg', 'Stage', 'Time (EEST)', 'Name', 'Length', 'Winner', 'Time', 'Avg. spd.', 'Rally leader']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1 (2/3 Aug)', 'SS1', '20:00', 'Killeri 1', '2.50km', 'C. Atkinson', '1:20.6', '111.66km/h', 'C. Atkinson']
SQL:

assistant: SELECT COUNT("Leg") FROM "Table" WHERE "Stage" = 'SS17';