The Securities and Exchange Commission yesterday suspended from business for varying periods a Washington brokerage firm and two of its former executives for allegedly defrauding some of the firm's customers.

Named in the nonjudicial proceeding were First Georgetown Securities Inc.; Eugene A. Jewett, who was president of the firm: and Geoffrey A. Kligman, a former vice president.

All three agreed to the settlement and sanctions without admitting or denying the allegations made by the SEC.

The SEC alleged that the trhee "willfully violated the antifraud provisions of the securities laws by making false and misleading statements." TR FOR ADD 1

First Georgetown allegedly advertised for sale Tennessee Valley Authorit bonds for sale and by "fraud and deceit," failed to inform investors of "the call provisions of, and yields on, the TVA bonds, the SEC said.

In another instance, the SEC said that the brokerage sold Quebec Hydro-Electric bonds to customers at inflated prices. At the time of the sals in 1977, the bonds to drop, but First Georgetown allegedly sold the securities at precrisis prices.

The SEC said the firm also deceived customers about the yields on bonds of the Government Services Administration, International Bank for Reconstruction and Development, and Maryland Health and Higher Education Facilities.

First Georgetown also allegedly failed to inform customers of delays and errors in the handling of their accounts.

In setting the SEC action the brokerage agreed not to seek new business for 30 days. It also agreed to disgorge commissions earned on some of the allegedly fraudulent transactions.

Jewett is suspended from the brokerage business for 30 days, and is barred from any supervisory role in a brokerage for two years, after which he must clear any supervisory plans with the SEC. Jewett, who is a stockholder in First Georgetown, agreed to liquidate his interest in the firm.

Kligman is suspended for 50 business days and also is barred from any supervisory role for two years. He must return commissions he personally earned on the TVA transactions to customers who bought those bonds.

In addition, Kligman must establish a voting trust for his common stock in C.A. Kligman & Co., a Washington firm he controls. Kligman also agreed to take SEC-selected courses in the securities business prior to returning to the securities industry.

In a statement issued yesterday, Randall Marsh, now president of First Georgetown, said: "The firm has already taken steps to strengthen internal controls and procedures, including changes in personel . . . and will add additional safeguards under the germs of the settlement recurrence of its past difficulties."