MonoBehaviour.OnLevelWasLoaded(int)
Description

This function is called after a new level was loaded.

level is the index of the level that was loaded. Use the menu item File->Build Settings... to see what scene the index refers to. See Also: Application.LoadLevel.
	// Prints "Woohoo" when level 13 is loaded.

function OnLevelWasLoaded (level : int) { if (level == 13) { print ("Woohoo"); } }
using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void OnLevelWasLoaded(int level) {
        if (level == 13)
            print("Woohoo");
        
    }
}
import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def OnLevelWasLoaded(level as int) as void:
		if level == 13:
			print('Woohoo')

OnLevelWasLoaded can be a co-routine, simply use the yield statement in the function.