A new poll in California’s 10th district shows that state Assemblywoman Joan Buchanan (D) starts with a narrow — but statistically insignificant — advantage in the yet-to-be scheduled special election to replace Rep. Ellen Tauscher (D).

Tauscher has been nominated to a top post at the State Department, but she hasn’t resigned her East Bay House seat yet and thus no special election has been scheduled.

But a poll conducted by Buchanan and obtained Thursday by Roll Call showed her with a narrow lead in a hypothetical four-way special open primary.

In the initial poll question, Buchanan was preferred by 21 percent of voters, state Sen. Mark DeSaulnier (D) was the choice of 18 percent, San Ramon Mayor Abram Wilson (R) got 14 percent, and former state Assemblyman Guy Houston (R) took 13 percent.

The poll of 400 likely voters was taken Sunday and Monday for Buchanan by Fairbank, Maslin, Maullin & Associates. It had a 5 point margin of error.

Under California law, in a special Congressional election, candidates run in an all-party primary. If no one gets more than 50 percent of the vote, the top vote-getters from each party move on to a special general election.

Although Democrats have a 46 percent to 29 percent edge in voter enrollment in the district, both the Democrats and the GOP are expected to have multiple candidates running in the primary, which is why the poll was set up the way it was.

So far, only one candidate has entered the race — Adriel Hampton, a Democrat who is an assistant city attorney in San Francisco. But Buchanan and DeSaulnier are considered the likely frontrunners if they choose to run.

Buchanan was just elected to the Legislature last November, but she has held local and county offices for several years.

“Obviously, there remain many uncertainties about the potential special election, including its date and the final field of candidates,— the pollsters wrote in a memo. “Nevertheless, these early survey results show that Joan Buchanan’s base of initial support — as well as the appeal of her background and experience — would make her an extremely strong candidate should she choose to run.—