in the defence against the dark arts classroom, i think, because previously, all of the others have. ( i think)
One, in Defence Against the Dark Arts because of the DA
In "Harry Potter and the Half-Blood Prince," the Defence Against the Dark Arts classroom is located on the third floor of Hogwarts. It is situated near the Potions classroom, reflecting the close relationship between the two subjects in this book, especially with Professor Snape teaching Potions and Professor Horace Slughorn teaching Defense. The classroom is characterized by its dark, atmospheric decor, befitting the subject matter.
limgardiean leviosa
Amycus Carrow, a Death Eater, is the Defence Against the Dark Arts teacher.
If your talking about the DS game... It's in the Defence Against The Dark Arts classroom. I think you have to swap it for 3 stink pellets and 6 chess pieces... pretty sure.
Gilderoy Lockhart was the Defence Against the Dark Arts teacher in Harry Potter and the Chamber of Secrets.
when you climb up the stairs to get to the defence against the dark arts you'll see stairs headed to the right just before you reach the classroom.
Gilderoy Lockhart played the Defence Against the Dark Arts teacher, in Harry Potter's second year at Hogwarts (Chamber of Secrets).
Dumbledore's Army (DA)
Severus Snape (the D.A.D.A. teacher in Harry Potter's 6th. year).
Hogwarts