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_15059783_1 ( mountains_classification VARCHAR, winner VARCHAR, points_classification VARCHAR )

### Question ###
If winner is alejandro Valverde and the points Classification is by Erik Zabel, who is the mountain classification?

### Accurate SQL ###

SELECT mountains_classification FROM table_15059783_1 WHERE winner = "Alejandro Valverde" AND points_classification = "Erik Zabel"