How can i make else statement in assembly language 8086?

So this is my code trying to display a menu that allow users to choose which product they are interested,

mov ah,1
      int 21h
      mov bh,al
      sub bh,48
      
      cmp bh,1
      je Applewatch
      
      cmp bh,2
      je Iphone
      
      cmp bh,3
      je Airpod
      
      cmp bh,4
      je Macbook
      
      cmp bh,5
      je Ipad
      
      cmp bh,6
      je Imac

However, if a user entered a random character other than 1-6, the system will jump to the first choice. I wanted to make a validation that jump users back to making the choice again if receives invalid character and how can i achieve that? Sorry if this question sound duplicated but I'm new to assembly language 8086 as it is included in my current semester. Any help will be appreciated.