CREATE TABLE table_17257687_1 (episode_number VARCHAR, event_4 VARCHAR, event_1 VARCHAR)

On which episode number is event 4 The Wall and event 1 the Pendulum?
SELECT COUNT(episode_number) FROM table_17257687_1 WHERE event_4 = "The Wall" AND event_1 = "Pendulum"
SELECT COUNT("episode_number") FROM "table_17257687_1" WHERE "Pendulum" = "event_1" AND "The Wall" = "event_4"