D&C 107

 The Lord instructs - 

"There are, in the church, two priesthoods, namely, the Melchizedek and Aaronic, including the Levitical Priesthood."  (Doctrine and Covenants 107:1)

Of the Aaronic Priesthood, it - 

 

"...has power in administering outward ordinances."  (Doctrine and Covenants 107:14)

In my mind, the difference between Aaronic and Levitical (which is part of the Aaronic priesthood), Aaronic includes the office of priests in administering outward ordinances and covenants, the Levitical is in reference to offices of deacons and teachers who serve in priesthood duties.