Get in touch with Nelly at cornerspeed and get him to send you one down then you know you have the right one

I think all the filters are the same. Nelly will sort you out anyhow.

i had the same prob (genuine filter though) after filter and oil change it just kept leaking
didn't have time to change it till the next w/e so just kept an eye on the level
by the time it had got round to the following saturday it had cured itself
think id done about 200 miles

Genuine filter schmilter! use crossland's on my bikes,£2.65p same spec' as standard never had a problem,if bike leaks after change,just nip up by hand while still hot,remove filter with warm motor when time to change comes around,NO PROBLEM. Steve R. cornwall

When you fitted the new filter, did you smear a little oil on the o ring seal before fitting. This helps lube the seal when you tighten, rather than it being dry and gripping!

That is very important - you simply cannot tighten a filter properly if the rubber seal is dry.

Ditto.
I've lost count of the number of filters I've changed.
I just buy 2 or 3 from whatever supplier I see when I need them.
Sometimes they are ducati, sometimes not.
Never had a problem, cos they are always changed before they get to a tenth of their design life.
(Just think how hard a life these parts have to be designed to take, and then consider how often we change them !)

2nd or 3rd'ed or whatever. Both my bikes leak even if I do replace the washer unless they have grease on them.

Not just a question of design life though, it's design quality and more importantly in the case of filters, filtration level!! Half of these so called after market filters aren't good enough for a deep fat frier yet alone a highly stressed modern engine. Stick to known brands or OEM unless you know the manufacturers design specifications.
Systems not to skimp on; Brakes, Suspension, Tyres and Oil!

A genuine Ducati filter is only about £6, hardly worth any kind of risk associated with a non Ducati item for that kind of money i would have though.