The confusion is over, and Nobel Prize winner Donald J. Cram seems ready to laugh the whole thing off. The UCLA chemistry professor, who for years has been mistaken for another Southern Californian, a carpet cleaner named Donald O. Cram, received word Wednesday that he had won the prize, but not before Donald O. Cram was told he had won it.

Donald O., who has received mail intended for Donald J. for nearly two decades, initially thought the crack-of-dawn phone call from Stockholm was a joke. It wasn't until the secretary of the Swedish Royal Academy of Sciences phoned a second time that he realized the call was for real and probably intended for Donald J.

Donald O. -- who some years ago jokingly challenged Donald J. to a duel, saying L.A. wasn't big enough for both of them -- now wants to meet Donald J., and the chemist's colleagues think that's a good idea. Although the Nobel laureate was unavailable for comment yesterday, UCLA spokesman Harlan Lebo said he thought Donald O. shouldn't feel bad about the confusion, because Donald J. "was tickled about the whole thing." Lebo said the Nobel laureate "would love to meet {Donald O.}. It would be terrific." Lebo said the two aren't complete strangers, as they know someone in common -- Donald J.'s wife Jane. Evidently, Jane Cram met Donald O. Cram at a university function some years ago, and she even gave him a hug. Making light of the mix-up, Donald J. said of Donald O. in a statement: "He got the call but I got the prize."

Last night Donald O. was a guest on the "Tonight" show, offering Johnny Carson a few tips on rug cleaning.

The Roosevelt Medals

The 1987 Roosevelt Freedom Medals will be awarded in New York today to five outstanding Americans whose achievements have demonstrated a commitment to the principles of freedom enunciated by President Franklin D. Roosevelt in his speech to Congress on Jan. 6, 1941. Former speaker of the House Tip O'Neill will receive the FDR Freedom Medal from Pamela C. Harriman; Washington Post editorial cartoonist Herbert Block will receive the Freedom of Speech Award from Jack H. Watson Jr.; the Rev. Leon Sullivan will receive the Freedom of Worship Award from Christopher Roosevelt; Mary Lasker will receive the Freedom From Want Award from Marietta Tree and Jean Kennedy Smith, and diplomat George F. Kennan will receive the Freedom From Fear Award from Thomas J. Watson Jr.

Thatcher's Motherly Visit

British Prime Minister Margaret Thatcher and husband Denis will fly to Dallas this weekend to visit their son Mark and his wife Diane. "It's a short, entirely private visit to see her son Mark and her daughter-in-law," said a spokesman for the British Embassy here. Thatcher, recently selected the most important woman in the world in a survey of 250 newspaper editors, is expected to fly to Dallas Sunday from Vancouver, following a Commonwealth meeting there. She is expected to stay with her son for a couple of days and will not be making any public appearances. Mark Thatcher moved to Dallas in 1984 to take a reported $60,000-a-year job promoting Lotus sports cars.

Another Ride for Princess Anne

Britain's Princess Anne will be on horseback in this country again when she competes in the Royal Steeplechase in Nashville. The princess, daughter of Queen Elizabeth II, is to arrive Wednesday and will ride in the opening race Oct. 23. She then will retire to the royal enclosure to watch the final three races, which will include the $100,000 Queen Mother Supreme Novice Chase. Also on the program for the charity event are performances by country entertainers Restless Heart, Ray Stevens and Lee Greenwood. "Ticket sales are going really well so far," said a spokeswoman for the International Steeplechase Group, which is sponsoring the event to benefit the Save the Children Fund. All 40 royal enclosure boxes have been sold at $10,000 apiece.