Jumping audio script

using UnityEngine;
using System.Collections;

public class NewBehaviourScript : MonoBehaviour {
    public AudioClip jump_clip; // defining the audio clip being used

    void Start () {
        audio.clip = jump_clip;
    }

    // Update is called once per frame
    void Update () {
        if (Input.GetButtonDown("Jump"))
        {
            if(audio.isPlaying == true)
            {
                audio.Stop();
            }
            else
            {
                audio.Play();
            }
        }
    }
}