Problem with audio.Play , script.

So basicaly I have a script where I made variable

var ObjectSound : AudioClip;

then if I press button #

AudioClip = ObjectSound;

Audio.Play();

And I want it to play only once when I press that button and it does ,but when I press that button again it plays that sound again which is logic … but I want to play it only once on button press and if I press that button again I dont want to hear that sound again.

How do I do that?

there is already a boolean that tells you if there is a sound play:
audio.isPlaying

see the example here.