SELECT MIN("Year") FROM table_30989 WHERE "Championship" = 'US Open (2)'
What is the earliest year in which the result is championship US Open (2)?
CREATE TABLE table_30989 (
    "Outcome" text,
    "Year" real,
    "Championship" text,
    "Surface" text,
    "Partner" text,
    "Opponents" text,
    "Score" text
)