Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_79 ( time_retired VARCHAR, driver VARCHAR, laps VARCHAR, grid VARCHAR )

### Question ###
what is the time/retired when the laps is 6, the grid is less than 18 and the driver is clay regazzoni?

### Accurate SQL ###

SELECT time_retired FROM table_name_79 WHERE laps = 6 AND grid < 18 AND driver = "clay regazzoni"