CREATE TABLE table_204_593 (id DECIMAL, "year" TEXT, "chairperson" TEXT)

who served after maturi ramaro ?
SELECT "chairperson" FROM table_204_593 WHERE "year" > (SELECT "year" FROM table_204_593 WHERE "chairperson" = 'maturiramarao') ORDER BY "year" LIMIT 1
SELECT "chairperson" FROM "table_204_593" WHERE "year" > (SELECT "year" FROM "table_204_593" WHERE "chairperson" = 'maturiramarao') ORDER BY "year" NULLS FIRST LIMIT 1