Constant potion effect

I wanted to run a clock that would give myself a potion effect for 1 seconds "/effect @p 14 1 0", it worked however when the clock stopped and the potion effect ran out; in the inventory it displayed 0:00 but did not disappear. I then tried removing it with "/effect @p 14 0" and it stayed despite the command block displaying "Took Invisibility from [Player Name]"