what is the platform when the frequency (per hour) is 4 and the destination is west croydon?
CREATE TABLE table_58163 (
    "Platform" real,
    "Frequency (per hour)" real,
    "Destination" text,
    "Operator" text,
    "Line" text
)
SELECT SUM("Platform") FROM table_58163 WHERE "Frequency (per hour)" = '4' AND "Destination" = 'west croydon'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: what is the platform when the frequency (per hour) is 4 and the destination is west croydon? ### Input: CREATE TABLE table_58163 (
    "Platform" real,
    "Frequency (per hour)" real,
    "Destination" text,
    "Operator" text,
    "Line" text
) ### Response: SELECT SUM("Platform") FROM table_58163 WHERE "Frequency (per hour)" = '4' AND "Destination" = 'west croydon'