How many districts have John C. Calhoun as the incumbent?
CREATE TABLE table_2668352_16 (district VARCHAR, incumbent VARCHAR)
SELECT COUNT(district) FROM table_2668352_16 WHERE incumbent = "John C. Calhoun"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_2668352_16 (district VARCHAR, incumbent VARCHAR) Question: How many districts have John C. Calhoun as the incumbent? [/INST] SELECT COUNT(district) FROM table_2668352_16 WHERE incumbent = "John C. Calhoun" </s>