CREATE TABLE table_31417 ("Official name" TEXT, "INE code" FLOAT, "Name in Spanish" TEXT, "Name in Basque" TEXT, "Population  ( 2007 ) " FLOAT)

What is the official name of the municipality whose name in Basque is Bilar?
SELECT "Official name" FROM table_31417 WHERE "Name in Basque" = 'Bilar'
SELECT "Official name" FROM "table_31417" WHERE "Name in Basque" = 'Bilar'