"Londonderry Air" was accepted as an alternative answer.
I have to say that this is the name by which I've always known the tune, and I've never heard it called the Derry Air before.
If you type "derry air" into Google, it steers you towards Derry Airport, Londonderry Air, or an airline from The Simpsons (which the eponymous family used to fly to Ireland). If, on the other hand, you type Londonderry, it steers you towards Londonderry Air.
Wikipedia has a page for Londonderry Air; if you search for Derry Air, it redirects you to Londonderry Air.
I know we shouldn't use Google, let alone Wikipedia, as the font of all knowledge; but if it's wrong to call the tune by its more familiar name, somebody needs to tell them.
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