Table: us_house_2006_elections_4
Columns: district
incumbent
party
first_elected
results

Question: What district was a republican first elected in 2000?
SQL: SELECT "district" FROM us_house_2006_elections_4 WHERE "first_elected" = 2000 AND "party" = 'republican'

Question: In what district was incumbent Russ Carnahan elected after 2000?
SQL: SELECT "district" FROM us_house_2006_elections_4 WHERE "first_elected" > 2000 AND "incumbent" = 'russ carnahan'