Provide the name of competitors from Greece.
name refers to full_name; Greece refers to region_name = 'Greece';
SELECT T3.full_name FROM noc_region AS T1 INNER JOIN person_region AS T2 ON T1.id = T2.region_id INNER JOIN person AS T3 ON T2.person_id = T3.id WHERE T1.region_name = 'Greece'