How to check scene number and use it in an If statement?

I have an audio that is set to DontDestroyOnLoad() but I want it to destroy on certain scenes, is it possible to check that and make the audio only DontDestroyOnLoad() if it is a certain scene?

Here is my script currently:

using UnityEngine;
using System.Collections;

public class dialogueclassicexist : MonoBehaviour {
	void Awake() {
		DontDestroyOnLoad(gameObject);
	}
}

Awake is only called once, when the behavior is loaded, therefore it is not checking every scene because you are not loading a new one every scene. Try something like this.

 using System.Collections;
 public class AudioGSingle : MonoBehaviour {
     private static AudioGSingle instance = null;
     public static AudioGSingle Instance {
         get { return instance; }
     }
     void Awake() {
         if (instance != null && instance != this) {
             Destroy(this.gameObject);
             return;
         } else {
             instance = this;
         }
         DontDestroyOnLoad(this.gameObject);
     }
     void OnLevelWasLoaded(int lvlNum){
         if(Application.loadedLevelName == "gameover"){
            Destroy(this.gameObject);
         }
     }
}

Use the properties Application.loadedLevelName for String or Application.loadedLevel for int index.

if( Application.loadedLevelName == "MyScene")
    DontDestroyOnLoad(gameObject);

theLucre is completely right with his answer, however you can also make use of the inbuild function:

void OnLevelWasLoaded(int level)
{
	if(level == 123)	// the scene number
	{
		// Do something
	}
}

OnLevelWasLoaded() is automatically called whenever (take a guess) a level is loaded! (Suprise!)

Hope this helps~

Cerbi