Sooo....

Email Leica US in New Jersey ASAP and order a bulb adapter for your enlarger. Philips discontinued the 13139 years and years ago, so your hopes of finding a new one are about zilch. Order through Leica, not the Canadian seller on eBay, since the price is about half for the real deal. Still about $90, though.

There's also some fuss about the older V35 having a single-condenser mixing box, while the later ones had double-condenser boxes and supposedly more even light output. I've measured mine and have found a center vs. edge variance (in and older V35 with a bulb adapter and an EFY bulb) of about 1/5 of a stop. (.06 density variance), so you'll be fine with what you've got.