What is the sum of Silver when the total is less than 6, the rank is 6 and the Bulgaria is the nation?
CREATE TABLE table_name_19 (
    silver INTEGER,
    nation VARCHAR,
    total VARCHAR,
    rank VARCHAR
)
SELECT SUM(silver) FROM table_name_19 WHERE total < "6" AND rank = "6" AND nation = "bulgaria"
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 sum of Silver when the total is less than 6, the rank is 6 and the Bulgaria is the nation? ### Input: CREATE TABLE table_name_19 (
    silver INTEGER,
    nation VARCHAR,
    total VARCHAR,
    rank VARCHAR
) ### Response: SELECT SUM(silver) FROM table_name_19 WHERE total < "6" AND rank = "6" AND nation = "bulgaria"