user: Question: What was the Stage when Pascal Richard had the Mountains classification and Vladimir Poulnikov won?
Columns: ['Stage', 'Winner', 'General classification', 'Points classification', 'Mountains classification', 'Young rider classification', 'Trofeo Fast Team']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1a', 'Endrio Leoni', 'Endrio Leoni', 'Endrio Leoni', 'not awarded', 'Michele Bartoli', 'Jolly Componibili-Cage']
SQL:

assistant: SELECT "Stage" FROM "Table" WHERE "Mountains classification" = 'Pascal Richard' AND "Winner" = 'Vladimir Poulnikov';