Name the title of the episode where Pamela Hayden voiced the character 'Ruthie.'
"Pamela Hayden" is the person; voice the character 'Ruthie' refers to role = 'Ruthie'
SELECT T1.title FROM Episode AS T1 INNER JOIN Credit AS T2 ON T1.episode_id = T2.episode_id WHERE T2.person = 'Pamela Hayden' AND T2.role = 'Ruthie';