user: Question: Which course had a Rest day for the Race Leader?
Columns: ['Date', 'Course', 'Distance', 'Type', 'Winner', 'Race Leader']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['15 May', 'Milan to Turin', 'km (mi)', 'Plain stage', 'Giordano Cottur ( ITA )', 'Giordano Cottur ( ITA )']
SQL:

assistant: SELECT "Course" FROM "Table" WHERE "Race Leader" = 'Rest day';