user: Question: Who's the winner in stage 1a, where the leader in the young rider classification is Francesco Casagrande?
Columns: ['Stage', 'Winner', 'General classification', 'Points classification', 'Mountains classification', 'Young rider classification', 'Intergiro classification', 'Trofeo Fast Team']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1a', 'Moreno Argentin', 'Moreno Argentin', 'Moreno Argentin', 'not awarded', 'Francesco Casagrande', 'not awarded', 'Mecair-Ballan']
SQL:

assistant: SELECT "Winner" FROM "Table" WHERE "Young rider classification" = 'Francesco Casagrande' AND "Stage" = '1a';