RETURNING from the rubber-chicken circuit, Capitol Hill politicos have a disappointment in store. 209 1/2 is gone, and instead of its lacy-crusted zucchini pancakes and fudgy chocolate cake, they are going to find grated carrots and bean sprouts. The site has been taken over by Health's A-Poppin'.

209 1/2 owner Jason Wolin has always seemed a step ahead of the crowd. Just over a decade ago he wowed Georgetown with Hot Diggity Dog. Next he opened 209 1/2. Then he launched a series of restaurants but didn't stay around long to manage them. Wolin originals included Bootsie, Winky & Miss Maud; Champagne and Beaujolais; Foggy Bottom Cafe; Georgetown Bar & Grill and Gloria's in the old Intrigue location. The Wolin restaurant that remains to carry on the style and legacy of 209 1/2 as well as to occupy Wolin's attention is Mrs. Simpson's. That's where you can still find those zucchini pancakes.

UNDIPLOMATIC CONDUCT --

The clear winner in the complaints contest for 1987 was Ambasciata d'Abruzzo. In the single month after Mark and Gail Barnett reviewed it for The Washington Post Magazine, I received more complaints about that restaurant than any other all year. In part, the complaints can be explained by readers flooding a restaurant that had been nearly empty until then. But there is obviously more to the problem. Some readers who had been to the restaurant before and after the review complained that the fixed-price Festa dinner had reduced its offerings, the quality and portions had declined, and that service had turned indifferent after the review.

THE BABIED MAITRE D' --

The sweetest story of the season came from a diner at East Wind in Alexandria. He and his wife took their baby to the restaurant, planning to take her for a stroll if necessary. When the baby began to fuss and the father was about to take her for a walk, the mai~tre d'hotel approached and offered to hold the baby while the couple ate. As it turned out, he charmed the baby as well as her parents, carrying the infant on his shoulder as he seated other diners. And after dinner the mai~tre d' returned the child with thanks to her parents for letting him carry her.

KEEPING THE OVENS WARM --

Unfortunately, the Bread Oven's replacement on 19th Street, Epi d'Or, doesn't hold a candle to its predecessor in most of its cooking. Its bread-baking, however, keeps up that fine tradition. Not only is this very good bread available to carry out, it is priced very reasonably. Particularly good is the big round crusty boule, which sells for $1 a loaf.