On the biggest, most stupendous news day that third-grader Edward Dulin said he could remember in his 10 years, the release of the hostages in Iran raised immediate worry.

"If my father was gone as long as a hostage dad, my dog would bite him when he got home," Dulin said.

The hostages were freed yesterday just as Ronald Reagan became president and millions of Americans were transfixed by one of those extraordinary days that even third graders may never forget. At Columbia Hospital in Washington, women who were there to have babies kept pestering their nurses for news of the hostages. Bells, sirens and car horns sounded in the early afternoon across the city. Some who had come here for the inauguration danced in the streets when word raced across the Mall that the 52 Americans finally were free.

"Boy, I'll tell you this is just like a suspense movie," said George Patellis, owner of the People Pickle Kosher Deli on Connecticut Avenue, where he and his customers maintained a vigil beside a portable radio. First, there was "I, Ronald Reagan, do solemnly swear . . ." and then there was the bulletin that the wheels of the hostages' jet to freedom no longer rested on Iranian soil.

In Mrs. Turner's sixth-grade class at Forest Grove Elementary in Silver Spring, 23 children who seemed to know all about the shah of Iran, the trade of money for human lives and the agony of missing one's father applauded and whistled when the radio told them the bondage was over.

"The hostages are more important to me than inflation," said Bryan Kelly, 11. "The people who had to stay locked up and suffered are more important to me than the cost of popsicles and stuff. Now that the hostages are free, I can turn my attention to inflation."

His classmates, who booed at the radio when it said that an Iranian shouted "Down With America" at the departing planeload of Americans, turned their thoughts to how hard it will probably be for the hostages and their families to get to know each other again.

"They've been locked up for a year and four months and they probably don't know nothin'. They don't know about Mount St. Helens. They don't know about the food they've been eating. They could have been eating chopped-up cats and stuff like that. They will need to talk to doctors," said John Siarkas, 11.

Valerie McKee, 9, a fourth grader, was worried that the hostage families may have a hard time loving someone who's been gone so long.

"Now their families will sort of be used to not having them around for a long time. The hostage man might have a beard or thick eyebrows. He may be real skinny.They might not all get along. The families now know how to buy groceries and pay bills by themselves. Things could be tough."

President Carter did a very good job, the children in Mrs. Turner's class agreed yesterday, to get the hostages out. They don't go along with those who have taken potshots at the president's supposed weakness. Reagan may have scared the Iranians, all right, they said, but Carter is a nice man.

"People have been mean to Carter," said Susan Wiltrout, 11. "They said he was hiding under his bed in the White House. He was in a tight situation. If I was him, I would have hided under my bed, too."

Lacking the charity of the children, lawmakers in Richmond yesterday were not so forgiving. A generous and supposedly routine resolution to congratulate Carter for bringing home the hostages ran into some unforgiving spirits in the Virginia General Assembly.

"I must record my dissent to the resolution congratulating and commending President Carter," said state Sen. Ray Garland (R-Roanoke), who speaks with a studied Churchillian thunder. "We negotiated from a posture of apology and weakness and many concessions were made that will cost this country billions of dollars."

Repelled by this display of sour grapes on the day that Carter left the presidency, the Virginia Senate's other premier orator, Sen. Hunter Andrews (D-Hampton), struck back. The normally stately Senate echoed to Andrews' counterattack:

"May I remind the gentleman from Roanoke the campaign is over," Andrews barked. With the crystal chandeliers still tinkling to his outrage, half a dozen other Democratic senators jumped up to elaborate on their own indignation.

The sponsor of the resolution, Sen. Willard Moody (D-Portsmouth) declared himself "incensed that a member of the Virginia Senate would . . . play Monday morning quarterback" over the hostage issue. If not for Carter's patience, said Moody, the hostages might "be buried somewhere in Iran rather than be on a plane heading back home."

Sen. Joseph Gartlan (D-Fairfax) bemoaned the "bitter and rancid partisan juice that has been poured in the cup of joy by the senator from Roanoke."

At the Maryland General Assembly, the bitter and rancid partisan juices did not run quite so heavy. Gov. Harry Hughes held a press conference with House Speaker Benjamin Cardin and Senate President James Clark to declare "Return to Freedom Week."

"I am particularly pleased," Hughes said, "that President Carter will be able to greet the hostages in Germany. It has been a long and hard ordeal for the hostages and a long and hard ordeal for Carter."

Republicans in the Democrat-dominated Maryland legislature grumbled yesterday, however, because the Democrats refused to declare a recess for the swearing in of Ronald Reagan. For Carter's inauguration in 1977, the legislature called a recess, rented a bus to take its members to Washington and spent $50,000 for a float in the inaugural parade.

"I think it is a little insensitive that they wouldn't afford the inauguration of a Republican president the same respect of a Democratic president," huffed Republic Sen. Howard Denis.

At Columbia Hospital, a maternity hospital in Northwest Washington where 10 babies are born every day, Shirley Patterson gave birth to a healthy baby and said her delivery on the day the hostages were freed gave her a particular empathy for the suffering of parents.

"They [the hostage parents] never knew when their babies were coming home. When you have a baby at least you have a little idea [when it will arrive]," said the 25-year-old mother from Takoma Park.

Her husband, Victor Patterson, 26, a security guard, celebrated the arrival of his baby with a "Hip, hip, hooray." Since he worried about the hostages during all of the nine months he'd worried about his wife's pregnancy, Patterson greeted word of their release with another "Hip, hip hooray."

Not all the parents were delighted to be part of Washington's celebration. One mother complained that clanging church bells in the afternoon were annoying her newborn child. "It's keepng my baby up," she said.

Back at Forest Grove Elementary, where the children had heard carping that the release of the hostages had somehow humiliated the United States, there was Matthew Levi, 12, who emphatically disagreed:

"That is silly grown-up talk, I think kids have a better view of this thing than grown-ups. All the grown-ups seem to care about is, you know, the pride of the country. We didn't want people to die."