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_16751596_16 (republican VARCHAR, lead_margin VARCHAR)
### Question:
How many times did Saxby Chambliss have a lead margin of 21?
### Answer:
SELECT COUNT(republican) AS :_saxby_chambliss FROM table_16751596_16 WHERE lead_margin = 21