user: Question: Who led the metas volantes classification for stage 4?
Columns: ['Stage', 'Winner', 'General Classification', 'Points Classification', 'Mountains Classification', 'Metas Volantes Classification', 'Team Classification']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Alberto Contador', 'Alberto Contador', 'Alberto Contador', 'Egoi Martínez', 'Iban Mayoz', 'Saunier Duval-Scott']
SQL:

assistant: SELECT "Metas Volantes Classification" FROM "Table" WHERE "Stage" = 4.0;