You have to make more logic s.
If you have 2 animations "walking""jumping"
You need also 3 variable walk = false jump = false walk_jump = false.
If left button pressed set walk to true , if walk = true and jump = false set animation "walking".
if jump button pressed set jump to true , if jump = true and walk = false set animation "jumping".
If left button and jump button are both pressed set walk_jump to true , set jump to false, set walk to false set animation to "jumping".
On landed set walk_jump to false.
But you have to play with that if you want to add and fire or run animations.