Which Bronze has a Silver of 15, and a Gold smaller than 20?
CREATE TABLE table_41978 (
    "Rank" real,
    "Nation" text,
    "Gold" real,
    "Silver" real,
    "Bronze" real,
    "Total" real
)
SELECT SUM("Bronze") FROM table_41978 WHERE "Silver" = '15' AND "Gold" < '20'
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: Which Bronze has a Silver of 15, and a Gold smaller than 20? ### Input: CREATE TABLE table_41978 (
    "Rank" real,
    "Nation" text,
    "Gold" real,
    "Silver" real,
    "Bronze" real,
    "Total" real
) ### Response: SELECT SUM("Bronze") FROM table_41978 WHERE "Silver" = '15' AND "Gold" < '20'