The chief of the leaders of the Levites was Eleazar son of Aaron the priest; he oversaw those responsible for the duties of the sanctuary.
KJV
And Eleazar the son of Aaron the priest [shall be] chief over the chief of the Levites, [and have] the oversight of them that keep the charge of the sanctuary.
ASV
And Eleazar the son of Aaron the priest shall be prince of the princes of the Levites, and have the oversight of them that keep the charge of the sanctuary.