what's the lowest elevation with highest point being charles mound
CREATE TABLE "table1_1416612_1" (
  "state" text,
  "highest_point" text,
  "highest_elevation" text,
  "lowest_point" text,
  "lowest_elevation" text,
  "mean_elevation" text
);
SELECT "lowest_elevation" FROM "table1_1416612_1" WHERE "highest_point"='Charles Mound';