CREATE TABLE table_204_863 (id DECIMAL, "state" TEXT, "city/county" TEXT, "population served" DECIMAL, "charter type" TEXT, "station name" TEXT, "web site" TEXT)

what is the number of people served by the rolla station ?
SELECT "population served" FROM table_204_863 WHERE "city/county" = 'rolla'
SELECT "population served" FROM "table_204_863" WHERE "city/county" = 'rolla'