A person who suffers from Pedophilia; that is, an adult who is sexually attracted to children.
Pedophilia is a mental disorder, not a sexual orientation or lifestyle choice. Specifically, it is a Paraphilia. The Paraphilias are characterized by recurrent, intense, sexual urges, fantasies, or behaviors that involve unusual objects, activities, or situations. Other examples of Paraphilias are Exhibitionism, Fetishism, Sexual Masochism, and Sexual Sadism.
Terms like "pedosexual" are misnomers and nothing more than political activism on the part of organized groups of pedophiles attempting to legitimize and legalize their abuse and predation of children.
Bob is is a pedophile because he is sexually attracted to little girls.