I am not a teacher and I just read your post. I think RonBee is correcting your question and suggesting you to say as him.
Regarding to your problem, do you find same problem for other teachers in the same class? You can share the problem with your colleagues. Of course, students may find it interesting in other subjects but boring in your.
If the noise is only due to the subject, you must change the teaching style. If the noise is due to the behavior of students, I think most teachers in your school face same problem as you.
(Please correct me if I say any wrong)