Bottom of dishwasher leaking when not running
Best case scenario is the brass bit just needs a bit more Teflon tape, and no parts are required. However, you need to figure out whether it is from the dishwasher to the brass L adapter, or the L adapter to the hose. If it is between the dishwasher and the L adapter, you have no choice but to take everything apart, because you can't possibly re-apply the Teflon tape otherwise.
If you need to replace anything, you may consider just outright skipping that L adapter and attach a hose directly to the dishwasher.  You should have enough floor clearance to do that.