Table:
0
A
B
C
D
E
F
1
District
Incumbent
Party
First elected
Result
Candidates
2
Washington 1
Rick White
Republican
1994
Re-elected
Rick White (R) 53.74% Jeff Coopersmith (D) 46.26%
3
Washington 3
Linda Smith
Republican
1994
Re-elected
Linda Smith (R) 50.18% Brian Baird (D) 49.82%
4
Washington 4
Doc Hastings
Republican
1994
Re-elected
Doc Hastings (R) 52.96% Rick Locke (D) 47.04%
5
Washington 5
George Nethercutt
Republican
1994
Re-elected
George Nethercutt (R) 55.58% Judy Olson (D) 44.41%
6
Washington 7
Jim McDermott
Democratic
1988
Re-elected
Jim McDermott (D) 80.96% Frank Kleschen (R) 19.04%

Questions and formulas:
Question:  how many party with district being washington 7
Formula: ROWS(UNIQUE(FILTER(C1, A1="Washington 7")))
Formula2: ROWS(UNIQUE(FILTER(C2:C6, A2:A6="Washington 7")))
Level: medium
Question: what's the latest first elected year
Formula: MAX(D1)
Formula2: MAX(D2:D6)
Level: easy
Question: what's the result with district being washington 7
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:F1,A1="Washington 7"),5))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:F6,A2:A6="Washington 7"),5))
Level: medium
Question: what being the minimum first elected with district being washington 7
Formula: MINIFS(D1,A1,"Washington 7")
Formula2: MINIFS(D2:D6,A2:A6,"Washington 7")
Level: easy