CREATE TABLE table_23155 ("LGA Name" TEXT, "Area  ( km 2  ) " FLOAT, "Census 2006 population" FLOAT, "Administrative capital" TEXT, "Postal Code" FLOAT)

What is the maximum 2006 census population of LGA name Opobo/Nkoro?
SELECT MAX("Census 2006 population") FROM table_23155 WHERE "LGA Name" = 'Opobo/Nkoro'
SELECT MAX("Census 2006 population") FROM "table_23155" WHERE "LGA Name" = 'Opobo/Nkoro'