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_99 (laps INTEGER, driver VARCHAR, grid VARCHAR)

### Question ###
what is the least laps when the driver is rolf stommelen and the grid is more than 18?

### Accurate SQL ###

SELECT MIN(laps) FROM table_name_99 WHERE driver = "rolf stommelen" AND grid > 18