What is the eccentricity when the semimajor axis is 20 au?
CREATE TABLE "the_epsilon_eridani_system" (
  "companion_in_order_from_star" text,
  "mass" text,
  "semimajor_axis_au" text,
  "orbital_period_s_day" text,
  "eccentricity" text,
  "inclination" text
);
SELECT "eccentricity" FROM "the_epsilon_eridani_system" WHERE "semimajor_axis_au"='20 au';