CREATE TABLE table_71127 ("Year" FLOAT, "Entrant" CLOB, "Class" CLOB, "Chassis" CLOB, "Engine" CLOB, "Tyres" CLOB, "Rank" CLOB, "Points" FLOAT)

What Chassis ranked 18th?
SELECT "Chassis" FROM table_71127 WHERE "Rank" = '18th'
SELECT "Chassis" FROM "table_71127" WHERE "Rank" = '18th'