CREATE TABLE table_50763 ("Rank" FLOAT, "City" TEXT, "Population" TEXT, "Definition" TEXT, "Country" TEXT)

What rank was Core Districts + Inner Suburbs and had a population of 10123000?
SELECT MAX("Rank") FROM table_50763 WHERE "Definition" = 'core districts + inner suburbs' AND "Population" = '10123000'
SELECT MAX("Rank") FROM "table_50763" WHERE "Definition" = 'core districts + inner suburbs' AND "Population" = '10123000'