CREATE TABLE table_15813 ("Department" TEXT, "Head" TEXT, "Full professors" FLOAT, "Honorary professors" FLOAT, "Lecturers" FLOAT)

What is the average number of honorary professors in the economics department with 1 lecturer?
SELECT AVG("Honorary professors") FROM table_15813 WHERE "Lecturers" = '1' AND "Department" = 'economics'
SELECT AVG("Honorary professors") FROM "table_15813" WHERE "Department" = 'economics' AND "Lecturers" = '1'