List down all ratings of action film titles.
for General Audiences means rating = 'G'; Parental Guidance Suggested means rating = 'PG'; Parents Strongly Cautioned means rating = 'PG-13'; Restricted means rating = 'R'; Adults Only means rating = 'NC-17'; action film refers to category.name = 'action'
SELECT T1.description FROM film AS T1 INNER JOIN film_category AS T2 ON T1.film_id = T2.film_id INNER JOIN category AS T3 ON T2.category_id = T3.category_id WHERE T3.name = 'action'