Politics, supply and demand are finally working together to slow the climb in natural gas prices, the chairman of Washington Gas Light Co. told shareholders yesterday.

WGL Chief Executive Donald J. Heim cited two recent price cuts by gas pipeline suppliers and "an emerging industry position" on natural gas legislation as "encouraging signs" for natural gas users.

"These actions indicate that the upward spiral of gas prices is abating and that market forces are beginning to work," Heim said at the local gas utility's annual stockholders' meeting at the Washington Hilton.

Reviewing the company's operations, Heim said Washington Gas is curtailing its search for new gas wells after losing $346,000 last year on the gas exploration operations of its subsidiary, Crab Run Gas Co. Crab Run drilled only one dry hole last year and has four new gas wells waiting to be hooked up to pipelines, but is suffering from the glut of gas.

"We are experiencing the same problem as others in the business--trying to sell gas in a buyer's market," Heim added.

He said that, after several years of losses, the gas company's other principal subsidiary, Davenport Insulation Co., earned a small profit of $63,000--equivalent to 1 cent for each share of WGL stock.

The gas company executive said he is optimistic that Congress will act to hold down natural gas prices. He said Washington Gas opposes the Reagan administration's plan to end price controls on old natural gas and considers three other elements vital to new gas legislation:

* Limiting the amount of gas that producers can force their customers to buy under "take-or-pay" contracts that require buyers to pay for gas whether they need it or not.

* Eliminating what are called "most-favored nation clauses" in gas supply contracts that require every gas producer in an area to be paid the highest price paid to any other local producer.

* Allowing gas pipeline companies to renegotiate contracts that require them to pay more for gas than the open market price they can charge their customers.