OKAY, we admit that Washington does not have a major league baseball team and that both Oakland, Calif., and Arlington, Tex., do. We concede that Baltimore and Las Vegas both have convention centers and we are still, at least for now, without. But cheer up, greater Washington. In addition to the National Visitor Center and the Shirley Highway "mixing bowl," we will soon have something that none of those cow towns or urban sprawls with zip codes can even hope for: our very own Sotheby Parke Bernet real estate office. Class.

When you say Sotheby Parke Bernet (doesn't everybody?) you know you're not talking about the kind of real estate that might involve "taking back a second" or VA financing. This is nothing but uptown stuff in our own backyard, or as SBP puts it so well in its announcement of the May opening of the Georgetown (you were expecting Brookland, maybe?) office: "Washington is truly a sophisticated world capital."

Any trio that made its reputation and bankroll as "the world's oldest and largest firm of fine art and antique auctioneers" could not be expected to handle listings of mobile homes or tree huts, so very understandably SPB will handle only properties beginning at $250,000.

While it is reassuring to know that our Old Home Town is now a very fashionalbe address, you might want to know who some of our new neighbors who will be buying the farms of the Virginia hunt country and the estates of the Eastern Shore are likely to be. Sotheby Parke Bernet mentions in its communique "our diverse worldwide clientele" and a "private list of over 80,000 individuals." Among its "glamorous clients" who have purchased SPB-listed properties are Liza Minelli, Billy Joel and Robin Gibb of the Bee Gees.

The down side of all this fame and fortune, of course, is that all too soon what once was top dollar will become bottom line in the housing market. And for the future clientele at SPB of Georgetown, it will only hurt when they smile.