CREATE TABLE table_name_46 (points_classification VARCHAR2, general_classification VARCHAR2, stage VARCHAR2)

What's the points classification of Stage 18 when the general classification was Denis Menchov?
SELECT points_classification FROM table_name_46 WHERE general_classification = "denis menchov" AND stage = "18"
SELECT "points_classification" FROM "table_name_46" WHERE "18" = "stage" AND "denis menchov" = "general_classification"