Leader’s High! (2006)

Blurb:
Eleven-year-old Daichi’s father is the principal at a school for budding young magicians. Daichi doesn’t have much in the way of magical powers and has even less interest in the subject. But one day, his parents abruptly take off for vacation and Daichi finds himself appointed to take his father’s place! Complicating his life further is the fact that Yozora — the beautiful student council President — is convinced that she’s destined to be with Daichi. Daichi also has to contend with a student council and a resentful teacher.

Source: www.anisearch.com/manga/75