Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_71 ( stage VARCHAR, mountains_classification VARCHAR, winner VARCHAR )

### Question ###
What was the Stage when Pascal Richard had the Mountains classification and Vladimir Poulnikov won?

### Accurate SQL ###

SELECT stage FROM table_name_71 WHERE mountains_classification = "pascal richard" AND winner = "vladimir poulnikov"