Delete offline static mapping

Hi,

I’m not entirely sure how I ended up here. But I was trying to add a static mapping for a managed switch that runs my VLAN. When I go into Status > DHCP Leases. I now have 2 entries for the managed switch. One with the actual static mapping that I set and this other one that doesn’t list an ip address for it (see image).

How can I go about removing this failed first attempt at static mapping?

Thanks!