CREATE TABLE table_203_875 (id DECIMAL, "#" DECIMAL, "name" TEXT, "birth and death" TEXT, "office started" TEXT, "office ended" TEXT)

how long was geir vidalin in office ?
SELECT "office ended" - "office started" FROM table_203_875 WHERE "name" = 'geir vidalin'
SELECT "office ended" - "office started" FROM "table_203_875" WHERE "name" = 'geir vidalin'