user: Question: Who is the GC leader at Ávila - Segovia?
Columns: ['Stage', 'Date', 'Course', 'Distance', 'Winner', 'GC Leader']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '5 September', 'Córdoba', '161,7', 'Markus Zberg', 'Markus Zberg']
SQL:

assistant: SELECT "GC Leader" FROM "Table" WHERE "Course" = 'Ávila - Segovia';