Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_21 (silver INTEGER, rank VARCHAR, gold VARCHAR)
### Question:
What is the amount of silver for rank 11 having less than 0 gold?
### Answer:
SELECT MIN(silver) FROM table_name_21 WHERE rank = "11" AND gold < 0